x - 2y = 8
x = y = 1
A) one B) None C) Infinite
2007-01-20 04:34:11 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Sorry that is
x + y =-1
2007-01-20 04:57:23 · update #1
The way you wrote it, B, none.
Did you really mean x = y = 1? that's what ruins it. If x and y have to equal 1, then 1 - 2(1) = -1 not 8, so there's no answer.
x - 2y = 8
x + y = -1
Then there's one solution, (2, -3):
x - 2y = 8
-x - y = 1
-------------
-3y = 9
y = -3
x + (-3) = -1
x - 3 = -1
x = 2
Check:
2- 2(-3) = 2 + 6 = 8
2 + (-3) = 2 - 3 = -1
2007-01-20 04:38:39 · answer #1 · answered by Jim Burnell 6 · 0⤊ 0⤋
x-2y=8
x+y=-1
======
-x+2y=-8
x+y=-1
=======
3y=-9
y=-3
x-3=-1
x=2
The solution set is (2,-3)
Check:
2-2(-3)=8
2+6=8
8=8
2-3=-1
-1=-1
I hope this helps!
2007-01-20 05:04:35 · answer #2 · answered by Anonymous · 0⤊ 0⤋
None
2007-01-20 04:40:41 · answer #3 · answered by Andrew 6 · 0⤊ 0⤋
(x - 2y = 8
(x + y = -1 (-)
Addition:
(x - 2y = 8
(-x - y = 1 (-)
------------
-3y = 9
y = 9/3
y = 3
x + y = -1
x + 3 = -1
x = -1 + 3
x = 2
Answer a).
><
2007-01-20 07:26:01 · answer #4 · answered by aeiou 7 · 0⤊ 0⤋
none
2007-01-20 04:40:13 · answer #5 · answered by BENNETH[[98]] 2 · 0⤊ 2⤋
(B)
2007-01-20 04:53:24 · answer #6 · answered by Riyah 3 · 0⤊ 0⤋